1. Technical Field
Example embodiments of the present invention relate to wireless local area network technology, and more specifically, to interference alignment technology for controlling interference in an overlapping band.
2. Related Art
As information and communication technologies develop, various wireless communication technologies are developing. Among them, a wireless local area network (WLAN) is technology for wirelessly accessing the Internet at home or companies or specific service providing areas using mobile terminals such as personal digital assistants (PDAs), laptop computers, portable multimedia players (PMPs), smart phones, and tablet PCs based on wireless frequency technology.
Institute of Electrical and Electronics Engineers (IEEE) 802.11 has been under development as standards for wireless local area network technology. Wireless local area network technology according to the IEEE 802.11a standard operates based on an orthogonal frequency division multiplexing (OFDM) scheme and may provide a maximum transfer rate of 54 Mbps in a 5 GHz band. Wireless local area network technology according to the IEEE 802.11b standard operates based on a direct sequence spread spectrum (DSSS) scheme and may provide a maximum transfer rate of 11 Mbps in a 2.4 GHz band. Wireless local area network technology according to the IEEE 802.11g standard operates based on the OFDM scheme or the DSSS scheme and may provide a maximum transfer rate of 54 Mbps in the 2.4 GHz band.
Wireless local area network technology according to the IEEE 802.11n standard operates based on the OFDM scheme in the 2.4 GHz band and the 5 GHz band, and when a multiple input multiple output-OFDM (MIMO-OFDM) scheme is used, may provide a maximum transfer rate of 300 Mbps for four spatial streams. Wireless local area network technology according to the IEEE 802.11n standard may support up to a channel bandwidth of 40 MHz and may provide a maximum transfer rate of 600 Mbps in this case.
As such wireless local area networks are being spread more actively and applications using the same become more diverse, a need for new wireless local area network technology for supporting a throughput higher than a data processing rate supported by IEEE 802.11n is increasing. Very high throughput (VHT) wireless local area network technology is one of the IEEE 802.11 wireless local area network technologies proposed to support a data processing rate of 1 Gbps or more. Among them, IEEE 802.11ac is developing as a standard for providing the VHT in a band of 5 GHz or less, and IEEE 802.11ad is developing as a standard for providing the VHT in a 60 GHz band.
As use of the wireless local area network has recently been increased, neighbor access points are highly likely to use an overlapping band. Accordingly, there is a problem in that communication performance decreases in the overlapping band between neighbor access points.